1. Field
The described technology generally relates to a liquid crystal display and a driving method thereof.
2. Description of the Related Technology
A liquid crystal display (LCD) is one of the most common types of flat panel displays. The LCD generally include two sheets of display panels, a liquid crystal layer interposed therebetween, a data driver, a gate driver, a signal controller, and a power generator. The display panels generally include field generating electrodes such as a pixel electrode, a common electrode, and the like. The data driver supplies a data voltage to the display panel. The gate driver supplies a gate signal to the display panel. The signal controller controls the data driver and the gate driver. The power generator generates a power voltage for driving the display panel. The LCD also typically include a plurality of signal lines such as a gate line and a data line for applying the data voltage to the pixel electrode by controlling a switching element connected to each pixel electrode.
The pixel electrode can be connected to the switching element such as a thin film transistor (TFT) to receive the data voltage. An opposing electrode can be formed on the entire surface of the display panel to receive a common voltage Vcom. The pixel electrode and the opposing electrode may be positioned on the same substrate or positioned on different substrates. A desired image may be displayed by applying the data voltage and the common electrode to the pixel electrode and the opposing electrode to generate an electric field in the liquid crystal layer and controlling an intensity of the electric field to control transmittance of light passing through the liquid crystal layer.
The LCD can receive an input image signal from an external graphic controller, the input image signal stores luminance information of each pixel, and each luminance has a predetermined number. Each pixel can receive a data voltage corresponding to luminance information. The data voltage that can be applied to the pixel is represented as a pixel voltage according to a difference from the common voltage applied to the common electrode, and each pixel displays luminance. This can be expressed by a gray of the image signal that correlates to a pixel voltage. In order to prevent deterioration, that can occur from applying the electric field in one direction to the liquid crystal layer for a long time, a polarity of the data voltage for a reference voltage is often inverted for each frame, for each row, for each column, or for each pixel. Further, in order to prevent spots such as a vertical line of a display screen from being generated, polarities of the pixel voltages applied to adjacent pixels are different from each other.
The data driver of the liquid crystal display selects a gray voltage corresponding to the input image signal to apply the selected gray voltage to the data line as a data voltage. In the case of polarity inversion driving, since the polarity for the common voltage of the data voltage is changed for each frame, for each row, for each column, or for each pixel, a change in voltage can be two times of the pixel voltage. The amount of power used by gray voltage is often increased. As a result, power used by the power generator and the data driver may be increased.
The above information disclosed in the background section is only for enhancement of understanding of the background of the described technology and therefore it may contain information that does not constitute prior art.